Vitamin D-dependent calcium-binding protein. Changes during gestation, prenatal and postnatal development in rats

Area of Science:

• Perinatal Biology
• Endocrinology
• Nutritional Science

Background:

• Calcium metabolism is critical during the perinatal period.
• Intestinal calcium-binding protein (CaBP) is a marker for 1,25-dihydroxycholecalciferol (1,25(OH)2D3) activity.
• Understanding vitamin D's role in maternal-fetal calcium transfer is essential.

Purpose of the Study:

• To investigate CaBP variations in maternal and fetal tissues during late gestation and early postnatal life in rats.
• To correlate CaBP changes with calcium absorption and transfer dynamics.
• To explore the influence of vitamin D on these processes.

Main Methods:

• Quantification of CaBP concentrations in maternal duodenum, placentas, fetal membranes, and fetal intestines.
• Analysis of CaBP changes from late gestation through weaning.
• Assessment of CaBP distribution along the fetal intestine.

Main Results:

• Maternal intestinal CaBP increased near term, correlating with enhanced calcium absorption and likely increased 1,25(OH)2D3 production.
• Placental and yolk sac CaBP levels varied during gestation, suggesting roles in materno-fetal calcium transfer and potential vitamin D target sites.
• Fetal intestinal CaBP emerged late in gestation, increased markedly before birth, and showed a significant rise at weaning, indicating developmental regulation.

Conclusions:

• CaBP dynamics in rats during the perinatal period highlight the intricate regulation of calcium metabolism.
• Vitamin D likely plays a crucial role in maternal adaptation, placental transfer, and fetal intestinal development.
• The observed CaBP changes before birth and at weaning signify critical windows of intestinal maturation and vitamin D-mediated adaptation.